METHOD OF PRODUCING 7{62 -ACYLAMIDO-3-METHYLCEPH-3-Em-4-CARBOXYLIC ACID ESTERS

ABSTRACT

The invention relates to a process for the preparation of 7 Beta -acylamido-3-methylceph-3-em-4-carboxylic acid esters from 6 Beta -acylamido penicillanic acid 1-oxide esters in the presence of catalysts which are salts or complexes of acids with nitrogen bases having a pKb of not less than 4. The salts or complexes may be formed in situ.

o United States Patent {191 [111 3,725,399

Ellerton et al. 1 Apr. 3, 1973- [54] METHOD OF PRODUCING 7B- [51] int.Cl. ..C07d 99/24 ACYLAMIDO3-METHYLCEPH-3-EM-4- [58] Field of Search..260/243 C CARBOXYLIC ACID ESTERS 56 R t Cit d [75] Inventors: NormanV. Ellerton, Harrow; Wil- 1 e erences e llam F. Paradise, Windsor; PeterE. UNITED STATES PATENTS sandford Chalfom Peter of 3,275,626 9/1966Morin etal. ..260/243 c England [7 3] Assignee: Glaxo LaboratoriesLimited, Green- Prim ry Examiner-Nicholas S Rizzo ford, Middlesex,England t ey-Bacon & Thomas [22] Filed: Mar. 10, 1970 [57] ABSTRACT [21]Appl. No.: 18,283 The invention relates to a process for the preparationof 7/3-acylamido-3-methylceph-3-em-4-carboxylic acid 30 ForeignApplication priority Data esters from 6B-acylarnido penicillanic acidl-oxide esters in the presence of catalysts which are salts or Mar. 11,1969 Great Br tain ..l2,866/69 complexes of acids with nitrogen baseshaving 3 PK) Sept. 22, 1969 Great Britain ..46,622/69 f not less than 4The salts or complexes may be formed in situ. [52] US. Cl. ..260/243 C,424/246 18 Claims, No Drawings METHOD OF PRODUCING 7B-ACYLAMIDO-3-METHYLCEPH-Ia-EMA-CARBOXYLIC ACID ESTERS This invention is concerned.with an improved process for obtaining cephalosporin compounds. Inparticular the invention is concerned with the conversion of penicillintype compounds into cephalosporin type compounds.

The compounds referred to in this specification are generally named withreference to penicillanic acid and cepham. Penicillanic acid has thestructure:

(see J.A.C.S. 1962, 84, 3400 and J.Chem. Soc. i965, 5031). The termcephem refers to the basic cepham structure with a single olefinicdouble bond.

Cephalosporin antibiotics are of great interest in that a number of themare of value in the treatment of infections caused by pathogenicbacteria some of which are resistant to other antibiotics. Penicillincompounds are, currently, produced in greater quantities on anindustrial scale than are cephalosporin compounds and with I thecontinually increasing interest in cephalosporin compounds it is highlydesirable to have available alternative techniques for producing thelatter such as a simple process for converting compounds of thepenicillin type into cephalosporins.

The invention is thus principally concerned with the conversion of6B-acylamidopenicillanic acid l-oxide esters into7B-acylamido-3-methylceph-3-em-4-carboxylic acid esters.

In U.S. Pat No. 3,275,626 there is described a general method forpreparing antibiotic substances, including cephalosporins, whichcomprises heating a socalled penicillin sulphoxide, under acidconditions, to a temperature of from about 100 to about 175 C.

It is an object of' the invention to provide a novel process for therearrangement of penicillin compounds to cephalosporin compounds. Wehave found that the rearrangement can be effected in good yields bymeans of certain substances which exist as salts or complexes.

In many' instances the process can be effected with ease and economy ofoperation. It is not certain in each instance whether they are truesalts or complexes. For example, reaction of pyridine withorthophosphoric acid yields a crystalline material analyzing C H N- 2HPO4. For convenience we have described them as being salts although itshould be'understood that the term salts is interchangeable withcomplexes.-

Moreover, under the conditions of the reaction the salt or complex mayexist in a dissociated form.

According to an embodiment of the present invention therefore there isprovided a process for the preparation of7B-acylamido-3-methylceph-3-em-4carboxylic acid esters comprisingrearranging a 6B-acylamidopenicillanic acid l-oxide ester (referred toherein as the penicillin oxide) in a substantially inert organic solventin the presence of a salt of a nitrogen base having a pKb of not lessthan 4 and an acid, which salt may be formed in situ in the reactionmixture. The acid may be, for example, an organic sulphonic acid, aphosphorus acid or trifluoroacetic acid.

The organic sulphonic acid maybe for example, a hydrocarbyl (e.g.,alkyl, aralkyl or aryl) sulphonic acid (e.g., methane sulphonic acid,toluene-p-sulphonic acid, p-xylene sulphonic acid or naphthalene 2-sulphonic acid), or a pyridylsulphonic acid.

The phosphorus acid' may be orthophosphoric, polyphosphoric,pyrophosphoric or phosphorous acid or it may be a phosphonic acid. Thephosphonic acid may be an aliphatic, araliphatic or aryl phosphonicacid; the aliphatic, araliphatic or aryl group of such a phosphonic acidmay be a hydrocarbon group (e.g., a

lower alkyl, phenyl lower alkyl or phenyl group) or a hydrocarbon groupsubstituted by, for example, a halogen atom or a nitro group. Examplesof aliphatic phosphonic acids include the lower alkyl and substituted(e.g., halogeno) lower alkyl phosphonic acids such as methane phosphonicacid, ethane phosphonic acid, dichloromethane phosphonic acid,trichloromethane phosphonic acid and iodomethane phosphonic acid.Examples of aryl phosphonic acids include the benzene and substituted(e.g., halogeno or nitro) benzene phosphonic acids e.g., bromobenzenephosphonic acids and nitro-benzenephosphonic acids.

The nitrogen base may be either inorganic or organic. The expressionnitrogen base is used herein as a convenient expression for a basicsubstance containing nitrogen although it may include other hetero atomse.g., oxygen. We prefer however to use organic amines. Bases which maybe used have a pKb for protonation of not less than 4 (i.e., as measuredin water at 25 C). The base may be a polyfunctional base having anitrogen function with such a pKb for the first protonation step. Thebases preferably have a pKb i water of not less than 7. V

The organic base may be primary, secondary or tertiary; however, weprefer to employ weak tertiary or-. ganic bases. Illustrative of suchtertiary organic bases are the unsaturated heterocyclic bases such aspyridine, quinoline, isoquinoline, benzimidazole and homologues thereof,for example the lower alkyl substituted pyridines and quinolines such as11-, B- and 'ypicolines and 2- and 4-methylquinolines. Other substitutedheterocyclic bases which may be used include those substituted byhalogen (e.g., chlorine or bromine), acyl (e.g., formyl or acetyl),acylamido (e. g., acetamido), cyano, carboxy, aldoximino and the like.

Other organic bases which may be used include aniline and nuclearsubstituted anilines such as halogeno anilines (e.g., o-chloroaniline,mchloroaniline and p-chloroaniline); lower alkyl anilines (e.g.,o-methylaniline and m-methylaniline); hydroxyand lower alkoxyanilines(e.g., o-methoxyaniline and m-hydroxyaniline); nitroanilines e.g.,m-nitroaniline) and carboxyanilines (e.g., m-carboxyaniline) as well asN-lower alkyl anilines (e. g., N-methylaniline).

Preferred classes of salts of nitrogen bases are those obtained by thereaction of a phosphorus acid or a sulphonic acid with a nitrogen base,e.g., in substantially molar equivalents. Advantageous results have beenobtained in the process according to the invention when salts oforthophosphoric or a phosphonic acid are employed as catalyst. Examplesof phosphonic acids are the aliphatic and aryl phosphonic acidsdescribed above.

Another preferred class of salts is that obtained by reactingsubstantially molar equivalents of an acid with an aromatic heterocyclictertiary organic nitrogen base. Advantageous results have been obtainedin the process according to the invention when salts of pyridine,quinoline, isoquinoline or derivatives thereof substituted with loweralkyl, halogen, acyl, acylamido, cyano, carboxy, or aldoximino, areemployed as catalyst.

Particularly preferred salts of nitrogen bases are those obtained byreaction of a phosphorus acid with an aromatic heterocyclic, tertiaryorganic nitrogen base, particularly in substantially molar equivalentsAdvantageous results have been obtained in the process according to theinvention when salts of orthophosphoric or a phosphonic acid withpyridine, quinoline, isoquinoline, or such bases substituted by, forexample, lower alkyl, halogen, acyl, acylamido, cyano, carboxy, oraldoximino are employed. Thus useful catalysts include pyridine;2-methyland 4-methylpyridine; quinoline and isoquinoline salts oforthophosphoric, methane phosphonic, ethane phosphonic, iodomethanephosphonic, dichloromethane phosphonic, trichloromethane phosphonic,bromobenzene phosphonic and nitrobenzene phosphonic acids.

The salts for use in the process according to the invention may bederived from proportions of the acid and the base such that one or moreof the acidic function(s) is exactly neutralized by the base. Generally,we prefer to use molar equivalents of the base and the acid. If desired,however, molar proportion other than those specified above may be used,for example, a less than molar quantity of nitrogen base may be employedso that, in addition to the salt the catalyst also comprises some freeacid. Alternatively, a more than molar quantity of nitrogen base may beemployed to produce a salt the average composition of which correspondsto a material intermediate to a monoor di- (nitrogen base) salt. Thebase may be used in excess of the total molar requirement to neutralizethe acid function(s) but should not be used in large excess e.g., itshould generally not be used in amounts of 5 molar excess and greaterand consequently this precludes the use of bases as solvents for thereaction.

The optimal ratio of acid: base will depend on various factors includingthe nature of the acid and the base as well as the nature of thepenicillin oxide. The optimal ratio may be ascertained by preliminarytrial and experiment.

One preferred'salt for use in the process according to the invention isthat obtained in situ in the reaction mixture by the reaction ofsubstantially molar equivalents of pyridine and orthophosphoric acid.

Other preferred salts for use in the process according to the inventionare formed from pyridine and dichloromethane phosphonic acid. One isobtained by reaction of substantially molar equivalents of pyridine anddichloromethane phosphonic acid and is referred to herein asmonopyridinium dichloromethanephosphonate and another is obtained byreacting substantially 2 moles of pyridine with 1 mole of the phosphonicacid and is referred to herein as dipyridinium dichloromethanephosphonate.

Salts formed from a nitrogen base having a pKb of not less than 4 and aphosphonic acid are novel compounds and constitute a further feature ofthe invention. The phosphonic acid is preferably a lower alkane orhalogeno lower alkane phosphonic acid. Novel compounds thus includepyridinium trichloromethane phosphonate, N-methylaniliniumtrichloromethane phosphonate, bis(benzylammonium) trichloromethanephosphonate, a-picolinium trichlormethane phosphonate, pyridiniumo-bromo-benzene phosphonate, monopyridinium dichloromethane phosphonate,monoisoquinolinium dichloromethane phosphonate andmono-3-methylisoquinolinium dichloromethane phosphonate.

Monopyridinium dichloromethane phosphonate may, conveniently, beprepared by gradually adding pyridine to a solution of dichloromethanephosphonic acid in a polar solvent (e.g., a ketone such as acetone or alower alkanol such as methanol, ethanol, npropanol or iso-propanol).Monopyridinium dichloromethanephosphonate is a stable, white crystallinesolid melting at 142-5 C.

Other preferred salts are disclosed in the examples described below.

The process according to the invention is carried out in organic solventsince one may regulate more exactly reaction conditions such astemperature. Ordinarily, the penicillin oxide will be in solution in theorganic solvent. The solvent should be substantially inert to thepenicillin oxide used in the process and to the cephalosporin producedby the process.

Solvents which may be used include those described in US. Pat. No.3,275,626 and other publications describing the rearrangement reaction.However, particularly suitable solvents include ketones boiling at from120 C (e.g., l00-120 C), esters boiling at from 75-l40 C (e.g., l00-130C), dioxan and diethylene glycol dimethyl ether (diglyme). lllustrativeof those ketones and esters that may be used in the process according tothe invention are aliphatic ketones and esters having appropriateboiling points including ethyl methyl ketone, isobutyl methyl ketone,methyl n-propyl ketone, n-propyl acetate, n-butyl acetate, iso-butylacetate, sec-butyl acetate and diethyl carbonate.

The time for achieving optimum yields by the process according to theinvention varies according to the particular solvent employed. Therearrangements are conveniently carried out at the boiling point of thechosen solvent and, for those solvents boiling in the lower part of theranges quoted above, correspondingly longer reaction times, e.g., up to48 hours, may be required than for those solvents boiling at highertemperatures. Rearrangements in dioxan generally require times of 7-15hours to achieve optimum results whereas those carried out in methylisobutyl ketone generally require times of 1-8 hours. The yields in therearrangements are dependent, but to a lesser extent,

.on the concentration of the catalyst in the solvent, correspondinglylonger reaction times being required for lower concentrations ofcatalyst.

concentrations of the order of 35 percent.

The quantity of the salt used should not generally exceed 1.0 mole permole of the penicillin oxide; however, we generally prefer to use saltsin proportions of from 0.01 to 0.2 mole per mole of penicillin oxide.

The salts used in the process according to the invention producecomparatively little color during the rearrangement as compared withsimilar rearrangements carried out in the presence of an acid catalystsuch as a hydrocarbyl sulphonic acid. Byproducts commonly formed withsuch acid catalysts appear to only a much smaller extent and the use ofsalts has the practical advantage that, under our preferred conditions,it is unnecessary to use decolorizing agents and acid binding agentsbefore removing the reaction solvent.

The appropriate time interval for any particular reaction may bedetermined by testing the reaction solution by one or more of thefollowing procedures:

1. Thin layer chromatography, for example on silica gel, developing witha 2:1 mixture of benzene and ethyl acetate and rendering the spotsvisible by treatment with an iodine/azide solution Russell, Nature,1960, 186, 788). Where, for example, the starting material is the2,2,2-trichloroethyl ester of 6,3-phenylacetamidopenicillanic acidlB-oxide, the product (R 0.65) gives an orange/brown color whereas thestarting material (R 0.5) gives a dark yellow color.

2. Determination of the rotation after suitable dilution of the reactionmixture with for example, chloroform. Using the same starting materialas in (1) the rotation drops to between about a third to about a quarterof the initial value.

. Determination of the ultraviolet spectrum of a sample of the reactionmixture suitably diluted wit ethyl alcohol. Using the same startingmaterial as in (1) the calculated value for E at 264 nm rises to about100 for a successful reaction. Absorption maxima at higher wave-lengthsare preferably low or absent. This determination cannot be adapted whenketonic solvents are used as the reaction media.

Although satisfactory yields can be obtained by carrying out thereaction under normal reflux, it may be possible to improve the yieldsby inserting a desiccating agent (e.g., alumina, calcium oxide, sodiumhydroxide or molecular sieves) which is inert to the solvent in thereflux return line to remove water formed during the reaction.Alternatively the water formed during the reaction may be removed by theuse of a fractionating column the water formed being removed byfractional distillation.

After completion of the reaction the salt may be removed either beforeor after concentrating the reaction mixture. 1f the reaction solvent isimmiscible with water, the salt can be removed by a simple washingprocedure. On the other hand, if the reaction medium is miscible withwater a convenient purification technique is to remove the reactionsolvent (this may be achieved by distillation under reduced pressure)and then to purify the residue by any convenient process e.g.,chromatography on silica gel.

It has been found that the degree of conversion achieved by the processaccording to the invention may be such that complicated purificationprocedures can be dispensed with and the product isolated in asubstantially pure condition after a simple crystallization process.

Preferably, however, the product is isolated by pouring the reactionmixture into water, filtering off the product and, if desired, furtherpurifying by recrystallization from, or slurrying with, a suitablesolvent.

When using preferred catalysts, for example, pyridinium phosphate ormono-pyridinium dichloromethane phosphonate in 'dioxan solution, it maybe necessary only to evaporate off the solvent and to crystallize theproduct from a suitable solvent in order to obtain a high yield ofsubstantially pure product.

A color removal step e.g., by means of charcoal may be employed; howeverthis is not normally necessary in the preferred conditions of theprocess according to the invention.

The penicillin oxide used as starting material in the process accordingto the invention may be derived from a salt of6B-phenylacetamidopenicillanic acid or ofGB-phenoxyacetamidopenicillanic acid, obtained for example from afermentation process, by esterification of the carboxyl group at the3-position of the penicillanic acid and oxidation of the sulphur atom atthe 1- position. Alternatively the penicillin oxide may be obtained from6B-aminopenicillanic acid by acylation of the amino group at the6B-position, esterification of the carboxyl group at the 3-position, andoxidationofthe sulphur at the l-position.

The oxidation may be carried out as described by Chow, Hall and Hoover(J. Org. Chem. 1962, 27, 1381). The penicillin compound is mixed withthe oxidizing agent in an amount such that at least one atom of activeoxygen is present per atom of thiazolidine sulphur. Suitable oxidizingagents include metaperiodic acid, peracetic acid, monoperphthalic acid,mchloroperbenzoic acid and t-butyl hypochlorite, the latter beingpreferably used in admixture with a weak base, e.g., pyridine. Excessoxidizing agents may lead to the formation of 1,1-dioxide. The l-oxidemay be obtained in the 0:- and/or B-form.

Acyl groups at the 6fl-amino position of the penicillin oxide may be anydesired acyl group but should preferably be reasonably stable under theconditions of the rearrangement. Conveniently the acyl group at the6B-position is that of a penicillin obtained by a fermentation processe.g., phenylacetyl' or 'phenoxyacetyl. Such a group may not be thedesired group in the cephalosporin end-product but this can be obviatedby subsequent transformations described below. Another acyl group whichmay conveniently be used is the formyl group.

Alternatively, the acyl group at the 6fi-position of the penicillinoxide may be that desired in the cephalosporin compound, e.g., athienylacetyl or phenylglyoxylyl group, or it may be a precursor for thedesired acyl group e.g., an acyl group containing a protected functionalgroup such as a protected amino group. An example of such an acyl groupis a protected a-aminophenylacetyl group.

The amine protecting group is conveniently one which can subsequently beremoved by reduction or hydrolysis without affecting the rest of themolecule, especially the lactam and 7B-amido linkages of the resultingcephalosporin compound. A similar protecting group may also be used asthe esterifying group at the 3-COOH position and both groups can besimultaneously removed as described below. An advantageous procedure isto remove both groups at the last stage in the sequence. Protectedgroups include urethane, arylmethyl (e.g., trityl)-amino,arylmethyleneamino, sulphenylamino and enamine types. Such groups can ingeneral be removed by one or more reagents selected from dilute mineralacids, e.g., dilute hydrochloric acid, concentrated organic acids, e.g.,concentrated acetic acid, trifluoroacetic acid, and liquid hydrogenbromide at very low temperatures, e.g., 80 C. A convenient protectinggroup is the tertiary butoxycarbonyl group, which is readily removed byhydrolysis with dilute mineral acid, e.g., dilute hydrochloric acid, orpreferably with a strong organic acid, (e.g., formic acid ortrifluoroacetic acid), e.g., at a temperature of -40 C., preferably atroom temperature 25 C). Another convenient protecting group is the2,2,2-trichloroethoxycarbonyl group which may be split off by an agentsuch as zinc in acetic acid, formic acid, lower alcohols or pyridine.

The ester of the penicillanic acid is preferably formed with an alcoholor phenol which may readily be split off, e.g., by hydrolysis orreduction, at a later stage to yield the subsequently formed ceph-3-emcompound as the free acid. Alcohol and phenol residues which may readilybe split off include those containing electron-attracting substituentsfor example sulpho groups and esterified carboxyl groups, these groupsmay be subsequently split off by alkaline reagents. Benzyl ando-benzyl-oxyphenoxy ester groups may be removed by hydrogenolysisalthough this may involve catalyst poisoning. A preferred method ofremoval involves acid cleavage and groups which may be removed by acidcleavage include adamantyl, t-butyl, benzyl residues such asanisyl andthe residues of alkanols containing electron donors in the a-positionsuch as acyloxy, alkoxy, benzoyloxy, substituted benzoyloxy halogen,alkylthio, phenyl, alkoxyphenyl or aromatic heterocyclic. These radicalsmay be derived from benzyl alcohols such as p-methoxybenzyl alcohol,di-pmethoxyphenylmethanol, triphenylmethanol, diphenylmethanol,benzoyloxymethanol, benzoylmethanol, pnitrobenzyl alcohol and furfurylalcohol.

Alcohol residues which may be readily split off subsequently by areducing agent are those of a 2,2,2- trihalogenoethanol, e.g.,2,2,2-trichloroethanol, pnitrobenzyl alcohol or 4-pyridylmethanol.2,2,2- Trihalogenoethyl groups may conveniently be removed byzinc/acetic acid zinc/formic acid, zinc/lower alcohol or zinc/pyridineor by chromous reagents; pnitrobenzyl groups may conveniently be removedby hyrogenolysis and 4-pyridylmethyl groups may conveniently be removedby electrolytic reduction.

Where the ester group is subsequently removed by an acid catalyzedreaction, this may be effected by using formic acid or trifluoroaceticacid (preferably in conjunction with anisole) or alternatively by usinghydrochloric acid e.g., in admixture with acetic acid.

We particularly prefer to use those penicillin oxides having adiphenylmethoxycarbonyl, a 2,2,2- trichloroethoxycarbonyl, at-butoxycarbonyl, a pnitrobenzyloxycarbonyl, benzoylmethoxycarbonyl orp-methoxybenzyloxycarbonyl group at the 3-position in the processaccording to the invention because the ceph-3-em compounds formed fromesters of this type do not appear to undergo appreciable A Aisomerization in the desterification reaction.

Where the product of the rearrangement is a 7B- acylamidoceph-3-emcompound not having the desired acyl group, the 7fl-acylamido compoundmay be N- deacylated, if desired after reactions elsewhere in themolecule, to yield the corresponding 7B-amino compound and the latteracylated with an appropriate acylating reagent.

Methods of N-deacylating cephalosporin derivatives having 7B-acylamidogroups are known ane one suitable method comprises treating a7B-acylamidoceph-3- em-4-carboxylic acid ester with an imide-halideforming component, converting the imide halide so obtained into theimino ether and decomposing the latter. If desired, the ester group maybe split off by hydrolysis or hydrogenolysis to yield the 4-carboxylicacid. Suitable readily removable ester groups are described above.

Suitable imide halide forming components include acid halides derivedfrom the phosphorus acids, the preferred compounds being the chloridessuch as, for example, phosphorus oxychloride or phosphoruspentachloride.

This method of N-deacylation is described in greater detail in BelgianPat. No. 719,712. N-Deformylation of a 7B-formamido group may beeffected with a mineral acid at a temperature of minus 15 to 100 C,preferably +l5 to 40 C. A convenient reagent for the N-deformylation isconcentrated hydrochloric acid in methanol or, preferably, in dioxan ortetrahydrofuran since undesirable transesterification reactions thattend to occur in methanol are thereby avoided.

In order that the invention may be well understood the followingExamples are given by way of illustration only.

In the Examples, unless otherwisestated, thin layer chromatography (TLC)was carried out on silica gel using a mixture of benzene and ethylacetate (2:1) as the developing solvent and detecting the spots withiodine/azide solution.

EXAMPLE 1 2,2,2-Trichloroethyl 6B-phenylacetamidopenicillanate lB-oxide(l9.28g., 4O mmole.) was dissolved in warm dioxan (400 ml). Pyridiniumphosphate (C H N' 2H PO,, 0.0704g., 2.56 mmole.) was added and thesolution was heated under reflux for 16 hours in an apparatus designedso that the condensed solvent passed through calcium oxide (6-12 mesh ca40 g.) before returning to the reaction vessel.

The cooled mixture was evaporated under reduced pressure to give a gumwhich was treated with warm ethyl alcohol [industrial methylated spirits(IMS); 20 ml.]. A solid crystallized, and the mixture was refrigeratedfor 3 hours and filtered. The collected solid was washed with lMS (10ml.) and diethyl ether (20 ml.) and dried to give 2,2,2-trichloroethyl3- methyl-7B-phenylacetamidoceph-3-em-4-carboxylate (l2.4g., 66.9percent of theory) [011 51.9 (C, 1.0 in CHCl mp l624.

A second crop (1.65g; 8.9 percent of theory) was obtained from theliquors [01],, 52.6 (C, 1.0 in CHCl,); mp l1.

EXAMPLE 2 A mixture of 2,2,2-trichloroethyl6B-phenylacetamidopenicillanate lfl-oxide (4.82g. 1O mmole), pyridine(0.078g., l mmole.), orthophosphoric acid (specific gravity 1.75;0.112g. l mmole.) and isobutylmethyl ketone (200 ml.) was boiled underreflux for 3 hr. The solution was cooled and then washed with water 1 X100 ml., 1 X 50 ml.). The organic phase was evaporated, under reducedpressure and the resultant gum was dissolved in ethyl alcohol (l.M.S.;20 ml.)

The solution was evaporated to dryness and the solid residue wastriturated with ethyl alcohol (l.M.S.; 15 ml.). The suspension wasstored for 16 hr at C and filtered. The collected solid was washed withether and dried to yield 2,2,2-trichloroethyl3-methyl-7B-phenylacetamidoceph-3-em-4-carboxylate (3.20g., 69.0 percentof theory), mp. 16l-2, [11],, 52.1 (C, 1.0 in CHC1 EXAMPLE-32,2,2-Trichloroethyl 6B-phenylacetamidopenicillanate l 62 -oxide(4.82g., l0 mmole.) and pyridinium methane sulphonate (0.175g., 1mmole.) were dissolved in hot isobutyl methyl ketone (200 ml.) andheated under reflux for 1% hours. The solution was cooled and washedwith water (1 X 50 ml. and 1 X 25 ml.) before evaporating to drynessunder reduced pressure. The residual semicrystalline gum was trituratedwith ethyl alcohol (l.M.S. 20 ml.) and refrigerated for 4 hours. A solidwas collected by filtration, washed with ethyl ether (20 ml.) and driedin vacuo to give 2,2,2- trichloroethyl3-methyl-7B-phenylacetamidoceph-3- em-4-carboxylate (2.79g., 60.1percent theory), mp 160161,[a],,+55.5(CHC1 C=1.0).

A second crop (0.1g., 2.2 percent theory mp 160) was obtained from theliquors.

EXAMPLE 4 Pyridine (0.04 ml; 0.05 mole equivalent) and 88 percent w/vorthophosphoric acid (0.032 ml; 0.05 mole equivalent) were added ton-propyl propionate and the mixture boiled under reflux with thecondensate returned to the reaction flask via a column of calcium oxide(10g.). After ca minutes reflux the mixture was cooled slightly and2,2,2-trichloroethyl 6B-phenylacetamidopenicillanate 1 B-oxide (4.82g;0.01 mole) added. The mixture was refluxed for 2 hours, concentrated toa low bulk and the residue crystallized from ethanol (12 ml.) to give2,2,2-trichloroethyl 3-methyl-7B-phenylacetamidoceph-3-em-4-carboxylate, 3.04g (65.5 percent oftheory) m.p. 161-162 [a],,+ 52.2 (C, 0.8 in Cl-lCl A (ethanol) at 264 nm(E 130).

EXAMPLE 5 p-Methoxybenzyl 3-methyl-7B-phenylacetamidoceph-3-em-4-carboxylate was prepared by rearrangement of p-methoxybenzylofl-phenylacetamidopenicillanate lB-oxide.

The starting material may be prepared by one of methods (i), (ii) or(iii) below.

METHOD (i) p-Methoxybenzyl bromide (15.93 g., 79.2 mmole) was added to astirred solution of 6B- phenylacetamidopenicillanic acid lfl-oxide (25.1g., 72

mmole.) and triethylamine (10.08 ml 72 mmole.) in dryN,N-dimethylformamide (200 ml.). The mixture was stirred at roomtemperature for 16 hours, and

poured into ice-cold water (1,000 ml.) to precipitate a pale yellow oil.This was extracted into ethyl acetate (3 X ml.), and the combinedorganic extract was washed with 3 percent-aqueous sodium hydrogencarbonate solution (250 ml.) and water (3 X 200 ml.),

dried over anhydrous magnesium sulphate, and evaporated to give a paleyellow foam. The foam was dissolved in ethyl acetate (200 ml.) and anyresidual N,N-dimethylformamide removed by washing with water (2 X 250ml.). Some crystalline solid separated during the second washing; thiswas redissolved on dilution with more ethyl acetate. The ethyl acetatephase was filtered through anhydrous magnesium sulphate and evaporatedin vacuo to ca. 20 ml., when a crystalline solid had separated. Thissolid was filtered METHOD (ii) Ethyl chloroformate (3.9 ml., 40 mmole)and dry triethylamine (2.8 ml., 20 mmole) were added to a stirredsuspension of N-ethylpiperidinium 6B-phenylacetamidopenicillanate(17.9g-., 40 mmole) in dry methylene dichloride (200 ml.) previouslycooled to 0". The pale yellow solution was stirred at 0 for 30 minuteswhen p-methoxybenzyl alcohol (16.58 g., mmole) was added. The reactionmixture was allowed to warm to room temperature over half an hour andthen stirred at this temperature for a further'2.5 hours, washedsuccessively with 5 percent orthophosphoric acid ml.), pH 7.30.2M-phosphate buffer (150 ml.), water (150 ml.), and then evaporated togive pmethoxybenzyl 6B-phenylacetamidopenicillanate as a yellow syrup,t.l.c. (benzene-ethylacetate 2:1) R, 0.48, 0.65 (p-methoxybenzyl alcoholR,0.49).

The syrup was dissolved in dry methylene dichloride (50 ml.) and a1.8M-solution of monoperphthalic acid in ether (20 ml.) was added;phthalic acid began to precipitate immediately. The suspension wasstirred at room temperature for 1 hour and then washed with saturatedaqueous sodium hydrogen carbonate solution (4 X 50 ml.). The combinedaqueous layer was backwashed with methylene dichloride (50 ml.), and,these washings were combined with the organic phase, which was washedsuccessively with saturated aqueous sodium hydrogen carbonate solution(50 ml.) and water (2 X 50 ml.), dried over anhydrous magnesiumsulphate, and evaporated to give an orange syrup. This syrup wasdissolved in chloroform (100 ml.) and diluted with ether (150 ml.) togive the ester IB-oxide (8.54g., 45 percent), m.p. 146-148.5 [01],, 191(0 0.97; CHC1 METHOD (iii) A suspension of sodium(SB-p11enylacetamidopenicillanate (178.2 g., 0.5 mole) inp-methoxybenzyl chloride (94.0 g., 0.6 mole) and N,N-dimethy1formamide(500 ml.) was stirred at room temperature for 88 hours. The reactionmixture was cooled in an ice-bath while peracetic acid (40 percent w/v;100 ml., 0.525 mole) was added over 15 minutes, and then stirred at roomtemperature for a further 20 minutes. Slow dilution with water (1.2liters) caused the separation of a white crystalline solid which wasfiltered off and washed with water (3 liters). The solid was thenstirred for 5 minutes with ethanol (400 ml.), refiltered, washed withethanol (100 ml.) and dried to give the ester 13- oxide (2l3.5g.,91percent, m.p. 149 150, [01],, 201 (C 0.94 ;CHCl

p-Methoxybenzyl 6B-phenylacetamidopenicillanate IB-oxide was convertedinto p-methoxybenzyl 3- methyl-7B-phenylacetamidoceph-3-em-4-carboxylateby one of the following methods:

a. A solution of p-methoxybenzyl 6fl-phenylacetamidopenicillanatelfi-oxide (9.41g., 20 mmole.), pyridine (0.16g., 2 mmole.) and 89percent phosphoric acid (0.22g., 2 mmole.) in dry peroxide-free dioxan(200 ml.) was heated under reflux for 15.25 hr., the condensed vaporbeing passed through molecular sieves (Linde 4A,1/16 inches; 40 g.)before returning to the reaction vessel. T.L.C. (benzene-ethyl acetate,2:1) showed only a trace of starting lfl-oxide remaining on sprayingwith iodineazide reagent. The dioxan was removed at 30/15mm. to give abrown gel which was triturated with I.M.S. (50 ml.). The resulting palebrown gel was collected, washed with I.M.S. and ether, and dried to givep-methoxybenzyl 3- methyl-7B-phenylacetamidoceph-3-em-4-carboxylate(6.025g., 66.5 percent, [01],, 44 (C, 1.24; CHCl )t,,,,,,,(EtOl-1) 228nm. (E 355 and 264-274 nm. (E 134), n.m.r. (CDCl 77.92

(ethanol) 226 nm. (E 361.5) and 269 nm. 1m

c. A reaction similar to that described in (b) but using pyridine (320mg., 4 mmole) and monopyridyl dichloromethanephosphonate (488 mg., 2mmole) gave, on removal of the dioxan, an orange gelatinous solid whichwas crystallized from boiling methanol (250 ml.) to give the ceph-3-em-ester as needles which were filtered off, washed with ether (20ml.) and dried (6.08g., 67 percent, m.p. 15l152.5, [a],,+ 390 (c 1.08;CHCl A (ethanol) 227 nm. (E 392) and 269 nm. (E 175). The filtrate andwashings were evaporated to ca. 75 ml. when a gel began to separate.This was redissolved by heating to reflux; cooling gave a second crop ofthe ceph-3-em ester as needles (1.28 g., 14 percent, m.p. l49150.5, [0:139 (0 0.98; Cl'lCl A (ethanol) 227 nm.(E, 164).

EXAMPLE 6 a. A solution of 6fl-phenylacetamidopenicillanic acidlfi-oxide (7.02 g. 20 mmole.), phenacylbromide (4.02 g., 20 mmole.) andtriethylamine (2.02 g., 20 mmole) in dry N,N-dimethylformamide (100 ml.)was stirred at room temperature for 1 hour, poured into water (700 ml.),and extracted with methylene dichloride (200 ml.). The combined organicextract was washed with water (4 X 350 ml.), dried over anhydrousmagnesium sulphate and evaporated to give a yellow foam (8.81 g.), whichwas purified by chromatography on silica gel (340 g.) usingbenzene-ethyl acetate mixture as eluent.

(C -C1183) integrated for 2.64 protons relative to 76.22 (C H OCHEvaporation of the combined filtrate and washings and crystallizationfrom I.M.S. ether gave a second crop of less pure ceph- 3-em ester(0.69g., 7.6 percent), n.m.r. (CDC1 77.92 integrated for 2.25 protonsrelative to 16.22. b. Pyridine (320 mg., 4 mmole) and 89 percentphosphoric acid (220 mg., 2 mmole) were added to a solution of the esterIB-oxide (9.41 g., 20 mmole) in dry, peroxide-free dioxan (200 ml.), andthe mixture was heated under reflux for 16 hours so that the condensedvapors passed through a bed of molecular sieves (Linde 4A, 1/16 inches;g.) before returning to the reaction vessel. T.l.c. (benzene-ethylacetate; 1:1) followed by spraying with iodine-azide reagent showed thata trace of starting lfl-oxide was present, so the reaction mixture washeated under reflux for a further 4 hours. The dioxan was removed at30/15 mm. to give an orange solid which was crystallized from boilingmethanol (300 ml.) to give p-methoxybenzyl 3-methyl-7B-phenylacetamidoceph-3-em-4-carboxylate as needles; they werefiltered off, washed with ether (20 ml.) and dried (5.81 g., 64percent), m.p. 151 l52, [01],, 38.5 (c 1.00; CHCI A (ethanol) 227 nm. (Ef' 382) and 269 nm. (E f 176). Evaporation of the filtrate and washingsto ca. 100 ml. gave a second crop of ceph-3-em ester (0.98g., 11percent), m.p. 150-152, [01],, +38 (c 0.98; CHCl A Benzene-ethyl acetate(1:1) eluted the phenacyl ester lB-oxide as an off-white foam (6.17 g.,66 percent),

[01],, 181 (c l; Cl-lcl A (ethanol) 243 nm.

b. A solution of phenacyl 6B-phenylacetamidopenicillanate IB-oxide(l.18g., 2.5 mmole.), pyridine (21 mg., 0.25 mmole.) and 89 percentphosphoric acid (28 mg, 0.25 mmole.) in dry, peroxide-free dioxan (50ml.) was heated under reflux for 27 hr., the condensed vapor beingpassed through molecular sieves (linde 4A, 1/16 inches; 40 g.) beforereturning to the reaction vessel. T.L.C. (benzene-ethyl acetate, 3:1)showed only a trace of starting 1 B-oxide remaining on spraying withiodine-azide reagent. The dioxan was removed at 30 15 mm. and theresidual yellow solid was dissolved with warming in a mixture of ethylacetate ml.) and 2N-sulphuric acid (100 ml.). The organic layer waswashed with water (100 ml.), combined with ethyl acetate back-wash ofthe aqueous layers, dried and evaporated to a crystalline solid. Thissolid was crystallized from I.M.S. to give phenacyl 3-methyl-7B-phenylacetamidoceph-3-em-4-carboxylate (0.56 g., 50 percent), m.p.184190, [111 +12 (C'l.0; CHCl A (ethanol) 244 nm. (E 430 with inflexionat 270 nm.(E 162).

A further crystallization from I.M.S. gave an analytical sample, m.p.-193", [01],, 7 (C 1.0; CHCl A (ethanol) 244 nm. (6 19,800) withinflexion at 270 nm. (e 7,480) (Found: C, 64.02; H, 5.0; N, 6.2; S, 7.0.c,,H,,N,o,s (450.5) requires C, 64.0; H, 4.9; N, 6.2; S, 7.1 percent).

EXAMPLE 7 a. p-Bromophenacyl bromide (3.2 g., 1 equiv.) was added inportions over 5 minutes to a stirred solution of6B-phenylacetamidopenicillanic acid IB-oxide (4.0 g.) and triethylamine(1.56 ml., 1 equiv.) in N,N-dimethylformamide (45 ml.). The reactionmixture was stirred at room temperature for 2.5 hours, poured into water(150 ml.) and extracted with ethyl acetate (2 X 75 ml.). The combinedorganic extract was washed repeatedly with water, dried, and evaporatedand the residue was crystallized from ethyl acetate-ether to give thepbromophenacyl ester lB-oxide (5.32 g., 86.5 percent), m.p. 150-153,[011 161 (c 2.03; tetrahydrofuran),

u (CHBr 1,800 (B-lactam) and 1,766 cm. CO R).

b. A solution of p-bromophenacyl 6B-phenylacetamidopenicillanatelB-oxide (1.095g., 2 mmole.), pyridine (16 mg., 0.2 mmole.) and 89percent phosphoric acid (22 mg., 0.2 mmole) in dry, peroxide-free dioxan(50 ml.) was heated under reflux for 30 hr., the condensed vapor beingpassed through molecular sieves (Linde'4A, 1/ 16 inches; 40g.) beforereturning to the reaction vessel. T.L.C. (benzene-ethyl acetate 3:1)showed no starting IB-oxide remaining on spraying with iodine-azidereagent. The dioxan was removed at 30l15 mm. and the residue wasdissolved with warming in a mixture of ethyl acetate (125 ml) and2N-sulphuric acid (125 ml.). The organic layer was washed with water,combined with the ethyl acetate backwash of the aqueous layers, driedand colorized by stirring with a mixture of anhydrous magnesium sulphateand charcoal, filtered and evaporated. The crystalline residue wasrecrystallized from hot 1.M.S. to give p-bromophenacyl 3-methyl-7fl-phenylacetamidoceph3-em-4-carboxylate (0.50g., 47 percent),m.p. 194198 [01],, 8 (C 1.05; CHCl k (ethanol) 258 nm. 25,900).

A further crystallization from l.M.S. gave an analytical sample, m.p.196199.5, [11],, 9 (C 1.0; Cl-lCl (Found: C, 54.3;1-1, 4.1; Br, 14.9; N,5.0; S, 5.8 C 11 BrN O S (529.4) requires C, 54.4; H, 4.0; H, 4.0; Br,15.1;N,5.3;S,6.l percent).

EXAMPLE 8 2,2,2-Trichloroethyl 7B'-(N-t-butoxycarbonyl-D-aaminophenylacetamido)-3-methylcepth-3em-4-carboxylate was prepared via the following reactionscheme;

2,2,2-Trichloroethyl 6B-phenylacetamidopenicillanate l2,2,2-Trichloroethyl hydrogen p-toluene sulphonate6fl-aminopenicillanate 2,2,2-Trichloroethyl6B-(N-t-butoxycarbonyl-D-aaminophenylacetamido )penicillanate2,2,2-Trichloroethyl 7fi-(N-t-butoxycarbonyl-D-aaminophenylacetamido)3methylceph-3-em-4-carboxylate a.2,2,2-Trichloroethyl 6B-phenylacetamidopenicillanate (1.86 g., 4 mmole)and pyridine (1.36 ml.) in ethanol-free chloroform (15 m1.) at 2 wastreated with phosphorus pentachloride (1.06 g., 5.2 mmole). The mixturewas stirred at 2 until the cloudy precipitate which appeared after theaddition had redissolved [usually about 30 min. a small amount ofgranular phosphorus pentachloride may still be present)], and methanol(10 ml.) was immediately added at such a rate that the temperature didnot rise above 0. The solution was stirred for 2.5 hr. at 0, then pouredinto water (4 ml.) and the pH adjusted to 8.5 using sodium hydroxide andsodium carbonate. The organic phase was collected and combined withethyl acetate extracts of the aqueous phase. The combined solution wasdried (magnesium sulphate) and the solvent evaporated leaving a gum.This was dissolved in ethyl acetate (10 ml.), and treated with asolution of p-toluene sulphonic acid monohydrate (0.70 g., 3.7 mmole) inethyl acetate (4 ml.). After 30 min., the precipitate was collected byfiltration, giving 2,2,2-trichloroethyl 6B- amino-penicillanate hydrogenp-toluene sulphonate as a pale yellow powder (1.58 g., 78 percent),[01],, +l53.2 (C 0.43, waterzdioxan 1:9), 11 (Nujol) 2,630 (NI-1 1790(B-lactam), 1,762 co cmccu 1,145 emf" so,- 7 (DMSO-d 6) 2.50,-2.87 [two2-proton doublets (branches of a quartet), J8l-lz; aromatic protons],v4.41 (l-proton doublet, J4Hz.; 6-H), 4.87 (lproton doublet, J41-lz;5-11), 4.96 (2-p r oton singlet; CO Cl-1 CCL 5.35 (l-proton singlet; 3-H), 7.65 (3-proton singlet; CH -Ar), 8.24, 8.41

0 (two 3-proton singlets; 2-Me [Found: C, 39.7; H, 4.1; N, 5.1; S, 12.3.C H CQN O S requires C, 39.3; H, 4.00; N, 5.4; S, 12.7 percent] b.2,2,2-Trichloroethyl 6 B-aminopenicillanate, hydrogenp-toluenesulphonate (2.60 g., 5.0 mmole) and sodium hydrogen carbonate(0.43 g., 5 mmole) were dissolved in methylene chloride (10 ml.) andwater (10 ml.). The organic phase was collected and combined withfurther methylene chloride extracts (3 X 5 ml.) of the aqueous phase,the combined extracts washed with brine (20 ml.) and dried (magnesiumsulphate). Dicyclohexylcarbodiimide 1.03 g., 5 mmole) was dissolved inthis dried solution which was then treated with a solution ofD-a-t-butoxycarbonylaminophenyl acetic acid (1.33 g., 5 mmole). Themixture was stirred for 4 hr., the precipitate of dicyclohexylureafiltered off, and the filtrate refrigerated overnight. Furtherdicyclohexylurea was removed and the volatile material evaporated,leaving a residue which was dissolved in ethyl acetate (50 ml.). Thesolution was washed with 2N-hydrochloric acid (2 X 20 ml.) water (20ml.), 3' percent-sodium hydrogen carbonate (2 X 20 ml.) water (20 ml.)and brine (20 m1.), dried (magnesium sulphate), and the solventevaporated, leaving 2,2,2-trichloroethyl 6B-(N-tbutoxycarbonyl-Da-aminophenylacetamido) penicillanate' as a paleyellow solid (2.55 g., 88

percent), 11 (bromoform) 1,788 (B-lactam), 1,770 (CO C1-1 CCl 1,710,1,510 (NHCO t.Bu). 1,698 and 1,500 cm. (CONH), 1' (CDCI 2.66 (5-prot0nsinglet; phenyl protons), 3.28 (lproton doublet, .l8hz.; 7-NHCO), 4.37(El-proton multiplet; NHCO 5-H, 6-H), 4.80 (lproton doublet, J 6.5 Hz.;PhCH), 5.23 (2-proton singlet; CO CH CCl 5.48 (l-proton singlet; 3-H),8.41, 8.49 (two 3- proton singlets; 2-Me 8.60 (9- proton singlet; t-Bu).

c. Monoperphthalic acid (0.20 g., 1.1 mmole) in ether (0.79 ml) wasadded to a solution of 2,2,2- trichloroethyl6B-(N-tbutoxycarbonyl-D-aaminophenylacetamido)penicillanate (0.58 g., 1mmole) in methylene chloride (10 ml.) at The solution was allowed toreach room temperature,

kept for 15 min., diluted with methylene chloride (40 ml.), and washedwith 3 percent-sodium hydrogen carbonate (2 X 50 ml.) and water (2 X 50ml.), dried (magnesium sulphate), and the solvent evaporated, leaving asyrup which was triturated under petrol (b.p. 4060), giving 2,2,2-trichloroethyl6B-(N-t-butoxycarbonyl-D-aaminophenylacetamido)penicillanate lfl-oxideas an off-white solid (0.31 g., 51 percent), u,,,,,,, (bromoform) 1,800(B-lactam), 1,768 (CO CH CCl 1,710 (NHCO t.Bu) 1,695 and 1,515 cm.-(CONH), -r (CDCI 2.33 (l-proton doublet, J10 Hz; 7-NHCO), 2.64 (S-protonsinglet; phenyl protons), 3.98 (l-proton double doublet, .l 10, 4.5 Hz.;6-H), 4.41 (l-proton doublet, 15.5 Hz.; NH- CO,), 4.87 (l-protondoublet, J5.5 Hz.; PhCH), 4.97, 5.33 [two l-proton doublets (branches ofa quartet), J 12 Hz.; CO CH CCl 5.02 (l-proton doublet, 14.5 Hz.; -H),5.22 (l-proton singlet; 3- H), 8.24, 8.72 (two 3-proton singlets, 2-Me8.57 (9-proton singlet; t.Bu).

d. 2,2,2-Trichloroethyl 6B-(N-t-butoxycarbonyl-D-a-aminophenylacetamido) penicillanate IB-oxide (270 mg., 0.45 mmole.) andpyridinium phosphate (C H N2H PO,;9mg.,0.033 mmole.). in dry dioxan(3ml.) was heated under reflux for 16 hr. The solvent was evaporated,the residue dissolved in ethyl acetate (20 ml.), the solution washedwith water, dried, and the ethyl acetate evaporated leaving a glasswhich was triturated under petrol (b.p. 4060) giving2,2,2-trichloroethyl 7B-(N-tbutoxycarbonyl-D-a-aminophenylacetamido)-3-methylceph-B-em-4-carboxylate as an off-white powder (264 mg.). Althoughthin-layer chromatography (Merck silicagel, acetone: methylene chloride3:97 as developing solvent) showed a single spot, R, 0.39, the protonmagnetic resonance spectrum indicated a purity of ca. 50 percent. theremaining 50 percent was a mixture of products.

EXAMPLE 9 2,2,2-Trichloroethyl6B-(N-trichloroethyloxycarbonyl-D-a-aminophenylacetamido )pencillanate1B- oxide (328 mg., 0.45 mmole.) and pyridinium phosphate (C H N-2H PO9mg., 0.033 mmole.) in dry dioxan (3rnl.) was heated under reflux for 16hr. The solvent was evaporated, the residue dissolved in ethyl acetate(20 ml.), the solution washed with water,

dried, and the ethyl acetate evaporated leaving a glass which wastriturated under petrol (b.p. 4060) giving 2,2,2-trichloroethyl7B-(N-trichloroethyl-oxycarbonyl-D-a-aminophenylacetamido)-3-methylceph-3-em-4- carboxylate as anoff-white powder (294 mg.). Although thin-layer chromatography (systemas above) showed a single spot, R 0.72, the proton magnetic resonancespectrum indicated a purity of ca. 30 percent, the remaining percentbeing a mixture of products.

EXAMPLE l0 2,2,2-Trichloroethyl 6B-phenylacetamidopenicillanate IB-oxide(4.82 g., 10 mmole.), N-methylaniline (0.107 g. 1 mmole.) andorthophosphoric acid (Specific gravity 1.75; 0.1 12 g., 1 mmole.), wereadded to isobutylmethyl ketone (200 ml.) and the mixture was boiledunder reflux for 1.25 hr. N-methyl-aniline (0.107 g., l mmole.) andorthophosphoric acid (Specific gravity 1.75; 0.112 g. 1 mmole.) wereadded and boiling was continued for a further 2.75 hr.

The solution was cooled to room temperatu'reand washed with water (1 Xml., 1 X 50). The organic layer was evaporated to dryness and thesemi-solid residue was dissolved in ethyl alcohol (I.M.S.; 20 ml.). Thealcoholic solution was similarly evaporated and trituration of theresidue with ethyl alcohol (I.M.S.; 15 ml.) produced a crystallinesolid. The mixture was stored at 0C for 16 hr. The product was collectedby filtration, washed with diethyl ether and dried to yield2,2,2-trichloroethyl 3-methyl 7,B-phenylacetamidoceph-3-em-4-carboxylate(1.90 g., 41.0 percent of theory), m.p. l6l2, [a] 51.0 (C, 1.0 in CHClEXAMPLE 1 l 2,2,2-Trichloroethyl 6B-phenylacetamidopenicillanatelB-oxide (14.46 g., 0.03 mole) in dioxan (300 ml.) was treated withm-nitrobenzenephosphonic acid (0.609 g.) and pyridine (0.24 ml.) and thesolution refluxed for 16 hours. During the reflux the condensate waspassed through neutral alumina before returning to the reaction flask.The reaction mixture was concentrated in vacuo. The residue wastriturated with hot I.M.S. (30 ml.), cooled to room temperature andrefrigerated for 2 hours. The solid was collected by filtration washedwith I.M.S. (10 ml.) and diethyl ether (20 ml.) and dried at 40 in vacuoto give 2,2,2- trichloroethyl 3-methyl7Bphenylacetamidoceph-3-em-4-carboxylate (1 1.32 g., 81.4 percent of theory) as a whitecrystalline solid m.pt. -2; [01],, 52.8 (C 0.9 in Cl-lCl A (ethanol) at264 nm (E,,,,, 136.5).

Concentration of the mother liquors followed by crystallization at 0afforded a second crop (0.6 g., 4.3 percent) m.pt. 160-2[a] 52 (C 0.8 inCHCl EXAMPLES l2 65 Using a variety of solvents and catalysts 2,2,2-trichloroethyl 6B-phenylacetamidopenicillanate oxide was converted into2,2,2-trichloroethyl 3-methyl 7B-phenylacetamidoceph-3-em-4-carboxylateunder the conditions and in the yields summarized in Table 1.

TABLE 1 Yield Concn. as Catalyst of pen. percent Example M01. Solventoxide, Time, Number Base Acid equiv. (at b.p.) percent, hrs. theory Pridine.....-..... Phos horic acid 0.1 Diglyme..-... 0.33 45.3 ii y d0.05 i-Pr. propionate. 5 6 60. 2 1 0. 2 n-Butyl acetate. 5 6 49. 2 0.0250 5 1.75 64.0 16 0.05 ..-..do 5.0 1.5 47.5 Phosphorous acid 0. 1Isobutyl methyl ketone. 2. 5 5 48. 4 Phosphorous acid 2X0.125 n-Butylacetate 5.0 6.5 41. 4 p-Toluene sulphonic acid.. 0. 1 Isobutyl methylketonc. 2. 5 1. 5 48. 4 p-Xylene sulfonic ac 0. 1 .--..do 2. 5 4 48. 7Pyrophosphoric acid (1). 1 0 1 2. 5 5 41. 4 Trifluoro acetic acid 0. 12. 5 8 3 40 0. 1 2. 5 3. 75 44. 3 0. 1 2. 5 4. 0 38. 8 0. 1 2. 5 3. 541. 8 0. 1 2.5 3. 42.5 o-Methyl aniline 0.1 2. 5 3. 5 45. 6 m-Methylaniline. 0. 1 2. 5 3. 5 44. 2 oMethoxy aniline. 0.1 2. 5 3. 5 45. 6m-Nitro aniline. 0. 1 2. 5 3. 5 44. 3 m-Carhoxy aniline. 0.1 2. 5 4.540.0 m-Ilydroxy aniline. 0. 1 2. 5 4. 75 40.2 Pyridine.. 0. 1 2.5 4 37.7..do Trifluoro acetic acid...... 0.1 oxan 2.5 24 4.) 3-bromo pyridine.Phosphoric acid 0. 1 Isobutyl methyl kctone.. 2. 5 3. 5 48. lBenzimidazolc.... Phosphoric acid 0. 1 .d 2. 5 2. 0 54. 3 2-methylquinoline. ..do 0.1 2. 5 6. 5 43. 3 Phosphoric acid 0.1 2. 5 2. 75 68. 20 0. 1 2. 5 2. 3 63. 1 0. l 2. 5 2. 3 68. 5 0. 1 2. 5 6. 3 47. 8 0. 1 2L5 I5. 75 43. 2 Sulphaniline 0.1 2. 5 3 38.8 3-acetamido pyridine. 0.12.5 3. 25 66.4 3-acetyl pryidine. 0. 1 2. 5 2. 5 55. 8 4-acetamidopyridine. 0. 1 2. 5 l0. 5 32. 2 4-chloro pyridine Phosp one ac 0.1 2. 52.5 49. 2 4-a1doximino pyridine. Phosphoric acid 0.1 2. 5 2. 5 65.64-carboxy pyridine Phosphoric acid.. 0.1 2. 5 5 .56. 3 4'eyano pyridine.Phosphoric acid 1 0. 1 2. 5 3. 5 43. 4 3-iormyl pyridine. .do.. 0.1 2. 53. 5 52.8 Quinoline ....do... 0. 1 2.5 3.75 56. 8 4-methyl quinoline....Phosphoric aci 0. 1 2. 5 7. 25 55. 2 54.. B-hydroxy quinoline...Phosphoric acid 0.1 2.5 4.0 44. 2 2-chloro pyridine ..do 0.1 2.5 4.0 44.3 Methane phosphonic acl 0. 3 5 16 42. 7 Ethane phosphonic acid 0. 3 522.5 46.8 ..do.. Iodomethane phosphonic acid. 0.1 5 17 67.6 59 ..doTrichiloro methane phosohonic 0.05 .-do. 5 18. 5 60.6

2101 60 Dipyridine ..do 0.05 .....do 5 16 71 61 N-methyl aniline... do..0.1 do 5 16. 5 39. 2 62 Bis (benzyl amine)... ..do.. 5 16 52.1 63u-Picoline ..do 5 24 '51 64 Pyridine o-Bromo benzene phosphonic 0.1.....do 5 18 '52 ac 65 -do Phosphonic acid 0.05 .do -20 11 76. 5

1 Base salts not isolated. Z An additional 0.025 mol. equivalent of freephosphoric acid used. 3 Estimated from crude yield of 51.6%. 1

EXAMPLE 66 45 and stirred while pyridine (63 ml.) was added dropa. Amixture of aluminum chloride (268 g.; 2.0 mol.), phosphorus trichloride(88 ml. 1.0 mol.), and chloroform (160 ml. 2.0 mol.) was boiled underreflux for 2 hours. The solution was cooled and poured into methylenechloride (700 ml.), the vessel was washed with methylene chloride (2 X150 ml.) and the washes added to the main solution. The mixture wascooled to 20 and stirred vigorously while water (260 ml.; 14.4 mol.) wasadded at such a rate as to keep the temperature near 5. When additionwas complete the mixture was warmed to 18 and stirred a further minutes.The precipitated aluminum trichloride hexahydrate was filtered off andthe bed washed with methylene chloride (1 X 500 ml.; 2 X 250 ml). Waterml; 2.2 mol.) was added to the methylene chloride solution and themixture refluxed for 1 hour to complete the second stage of thehydrolysis. The methylene chloride was distilled off and the residue wastreated with methylene chloride (250 ml.) which was again distilled off.The

wise. The solid was filtered off and washed with cold acetone (3 X ml)and dried at room temperature in vacuo overnight to give crudemonopyridinium dichloromethanephosphonate (197.4 g.; 80.4 percent) m.p.l4l-2.

The crude salt was dissolved with stirring in boiling I.M.S. (410 ml.),cooled until crystallization commenced, then refrigerated for 3 hours.The product was collected and washed with acetone (3 X 50 m1.) and driedat 40 in vacuo to give monopyridinium dichloromethanephosphonate (188.6g.; 77.3 percent theory overall) m.p. 143 5. Free from ionizablechloride (no turbidity with silver nitrate in nitric acid).. Found: C,29.9; H, 3.3; Cl, 29.1;N, 5.9; P, 12.3; C l-1 C] NO P requires C, 29.5;H, 3.3; CI, 29.1; N, 5.7; P, 12.7 percent.

b. 2,2,2-Trichloroethyl 6B-phenylacetamidopenicillanate IB-oxide (96.4g; 0.2 mole) and monopyridinium dichloromethane phosphonate (1.95 g;0.008 moles) were added to dioxan (482 ml; treated with basic alumina)in a 3-necked flask, fitted with a stirrer and'condenser. The mixturewas stirred and brought to reflux, with the condensed vapors beingreturned through sodium hydroxide pellets. The solution was stirredunder reflux for a total of 8 hours when no starting material remained(TLC). The dioxan was removed under reduced pressure to leave a moistsolid. IMS (200 ml.) was added and the solid triturated for severalminutes to give a uniformly crystalline material. The mixture was leftat for 3 hours, when the solid was collected by filtration, washed withIMS (100 ml.),ether (100 ml.) and dried in vacuo at room temperature togive 2,2,2- trichloroethyl 3-methyl-7B-phenylacetamidoceph-3-em-4-carboxylate (75.1 g: 80.9percent theory yield) as a whitecrystalline solid, m.p. 162165 corrected, [01],, 53(c, 0.91 in CHCl A264 nm (E 130), TLC (benzene/ethyl acetate, 2:1 )1 single spot 11,065.The liquors were concentrated to give a second crop of the above product(2.3 g.; 2.5 percent theory yield).

dried in vacuo at room temperature to give 2,2,2- trichloroethyl3-methyl-7B-phenylacetamido-ceph-3- em-4-carboxylate (89.6 g.; 96.6percent theory), m.p. 156(corrected); [01],, 58 (CHCl A (ethanol) 264 nm(E, 121).

EXAMPLE 69 Preparation of salts of phosphonic acids A 12.5percentsolution of the acid in the appropriate solvent was treated with thebase, added dropwise, until no further precipitation occurred. The solidwas filtered off, washed with the same solvent as used for the reactionand dried in vacuo at 20 to give the required product. Samples wererecrystallized if necessary.

The following table gives the salts of the acid RP(O)(OH) which wereprepared in this manner. All the acids shown in the table formed themono-basic salt with the exception of trichloromethane phosphonic acidwhich gave the dibasic salt with benzylamine.

Salt

M.P. Found Required (corn) Acid R= Base Solvent degrees C H 01 N C H C1N Formula Cl C N-Methylanilinc. Ether 210-20 31.6 3.0 34.7 31.3 3.6 34.7CsHnNOaClaP C1 C- Pyridine .do 180-4 250 2.9 38.8 5.1 25.0 2.5 38.2 5.0CaHvNOsClaP C13C- Benzylamine do 198-202 43.8 5.1 25.6 6.5 43.5 4.9 25.76.8 C1sH2oNzOaClaP C1 C a-Picolino .dO 155-7 28. 8 3. 0 36. 5 4. 7 28. 73. l 36. 4 4. 8 C7HON 3C13P C12CH Isoquinoline Acetone. 143-7 40.5 3.324.0 4.4 40.8 3.4 24.2 4.8 CioHioNoaolzP Cl2OH S-methylisoquinoline do.1474) 42. 4 4.0 23. 1 4.3 42. 8 3. 9 23.1 4. 6 CnHnNOaClzP m. 159 162corrected, 0: 53.l c, 0.97 in EXAMPLE 70 Cl-lCl A 264 nm (E,, 131), TLC(benzene/ethyl acetate, 2:1 single spot R, 0.65.

EXAMPLE 67 2,2,2-Trichloroethyl 6B-phenylacetamidopenicillanate lB-oxide(96.4 g; 0.2 mole), monopyridinium dichloromethanephosphonate (1.708 g;0.007 mole) and pyridine (0.56 ml; 0.007 mole) were added to dioxan (482ml; treated with basic alumina) in a three necked flask fitted with astirrer and condenser. The reaction and isolation of the product werecarried out as described in Example 66(b) to give 2,2,2- trichloroethyl3-methyl-7B-phenylacetamidoceph-3- em-4-carboxylate (73.5 g; 79.2percent theory yield) as a white crystalline solid, m.p. 161 .5-164.5corrected, [a],, 53.9 (c 0.91 in CHCl A 264 nm (E, 131), T.L.C.(benzene/ethyl acetate 2:1) single spot R,0.65.

A second crop (2.74 g; 2.95 percent theory yield) m.p. 160 162corrected; [01],, 53.6 (C 0.95 in CHCl,) A 264 (E 131), T.L.C. 1 spot,was obtained from the mother liquors.

EXAMPLE 68 2,2,2-Trichloroethyl fl-phenylacetamid'openicillanateIB-oxide (96.4 g.; 0.2 mole) and monopyridinium dichloromethanephosphonate (1.95 g.; 0.008 mole) were boiled under reflux in dryperoxide-free dioxan (482 ml.) and the condensate was run through acolumn of desiccant (sodium hydroxide pellets: 200 g.) before beingreturned to the reaction flask. The progress of the reaction wasfollowed by TLC. After 7.5 hours reflux no starting material remained.The solution was cooled to room temperature and poured into water (2.5liters) with stirring. The solid was isolated by filtration, washed withwater (2 X 100 m1.) and EXAMPLE 71 2,2,2-Trichloroethyl6B-phenylacetamidopenicillanate IB-oxide (48.2 g., 0.1 m.) and mono-3-methylisoquinolinium dichloromethanephosphonate (1.54 g., 0.005 m.) indioxan (482 ml.) were reacted (81.25 hours) and the. product wasisolated as described in example 66(b) to give 2,2,2-trichloroethyl3-methyl-7B3-em-4-carboxylate (30.42 g.: 65.5 percent theory yield, m.p.l62-4 C corrected, [01],, 52 (c, 0.8 in CHCl k f 264 nm (E 138).

EXAMPLE 72 v 2,2,2-Trichloroethyl3-methyl-7B-phenoxyacetamidoceph-3-em-4-carboxylate A solution of2,2,2-trichloroethyl 6B-phenoxyacetamidopenicillanate-1 B-oxide (2.45 g;5.0 m.mole) in dioxan (dried by passage through basic alumina, 50 ml.)was brought to reflux such that the condensed vapors were passed throughmolecular sieves (Linde 4A; 30g) before being returned to the reactionflask. The mixture was heated at reflux for 20 minutes and thendichloromethanephosphonic acid monopyridinium salt (0.1345 g; 0.52m.mole; 0.104 eq) and pyridine (0.039lg; 0.50 m.mole; 0.100 eq) wereadded. The refluxing was continued for hours after which time all thestarting material had been consumed (as determined by T.L.C. using 2percent acetone in methylene chloride as eluent, and potassiumiodideiodine-potassium azide solution as detecting spray reagent). Thedioxan was removed under reduced pressure and the residual yellow oildissolved in ethanol (Sml) and ether (5ml). Evaporation of this solutionto dryness left a pale yellow solid which upon trituration with etherml) containing methanol (0.5 ml) yielded the title compound as abuff-colored solid (1.45g; 60.5 percent) m.p. ll2l (uncorr.); [01],, 572(0, 1.19, CHCl Evaporation of the mother liquors and re-trituration withether (2 ml.) containing methanol (0.1 ml) gave a second crop as abuff-colored solid (0.436 g; 18.6 percent) m.p. l05-l14 (uncorr.)[01],," 53.4 (c. 1.20, CHCl EXAMPLE 73 a. t-Butyl6B-Phenylacetamidopenicillanate-1B- oxide 1 To a solution of6B-phenylacetamidopenicillanic acid lB-oxide (3.5 g; 0.01 mole) andpyridine (4.2 ml, 0.05 mole) in t-butanol (10 ml.) at 0, phosgene (2ml., 0.028 mole) was added over min., such that the temperature did notexceed 8. 5 Min. after the addition was complete, the cooling bath wasreplaced by a bath at 23 and stirring continued for 30 min. The mixturewas poured into sodium carbonate solution (75 ml., containing enoughalkali to give a final pH of 9), and extracted with ethyl acetate (3X50ml.). The combined organic extract was washed with water (50 ml.) andbrine (50 ml.), dried (magnesium sulphate), and the solvent evaporatedleaving a brown crystalline residue (1.95 g.). Treatment of this residuewith ether ml.) for min. gave t-butyl6B-phenylacetamidopenicillanate-lB-oxide as a fawn powder (1.20 g, 29percent), m.p. 147-149, [a],, 201 (c 1.00, dioxan), R 053 (Merck silicagel-coated plates; benzene:ethyl acetate 1:1 as developing solvent), A(CHBr 3,390 (NH), 1790 (fiHactam), 1,738 (CO t.Bu), 1,678, 1,502 (CONH),1,028 cm" (S=O), 1-(CDCl 2.69 (5-proton singlet; phenyl protons), 2.89(l-proton doublet, J 10 was hours, the refluxing dioxan being passedthrough a bed ether (60 mls) for 6 hours at 25, stood at 4 for 62 hoursand filtered; the residue was washed with ether (30 mls) and dried togive t-butyl 3-methyl-7B-phenylacetamidoceph-3-em-4-carboxylate (5.80 g,m.moles 65.5 percent), m.p. 120-123, [11],, 62 (c1.00, CHCl v (CHBr3,430 and 3,345 (NH), 1,780 (B-lactam), 1,720 (CO R), 1,680 and 1,510cm- (CONH), (CDCl MH 8.46 (9-proton singlet; t-butyl), 7.93 (3-protonsinglet; 3-methyl), 6.53 and 6.91 (2-proton AB-quartet, J=18 Hz; S-CH6.40 (2-proton singlet; Ph CH 5.11 (l-proton doublet J 47 Hz; 6-H): 4.29(l-proton doublet of doublets, J 9 and 4 Hz; 7-H), 3.32 l-protondoublet, J 9 Hz; N-H), 2.73 (5-proton singlet; Ph-), k (6) 257.5 (5.780)and 263.5 (5.780) (Found C, 59.9; H,

6.2; N, 6.8 S, 7,9 C H ,N O,S requires C. 61.8; H, 6.2;

We claim:

1. In a process for the preparation of a 7B-acylamido-3-methylceph-3em-4-carboxylic acid ester by heating a6B-acylamidopenicillanic acid l-oxide ester in a substantially inertorganic solvent in the presence of a catalyst, the improvement whichcomprises employing as catalyst a salt of an amine selected from thegroup consisting of pyridine; quinoline; isoquinoline; benzimidazole;pyridine, quinoline, isoquinoline or benzimidazole substituted by achlorine or bromine atom or a lower alkyl, formyl acetyl, acetamido,cyano, carboxy or aldoximino group; aniline aniline substituted by achlorine atom or a lower alkyl, hydroxy, lower alkoxy, nitro or carboxygroup; and N-lower alkyl aniline and his (benzylamine) and an acid.

selected from the group consisting of methane sulphonic acid,toluene-p-sulphonic acid, p-xylene sulphonic acid, pyridyl sulphonicacid, a phosphorus acid and trifluoroacetic acid. a

2. A process as defined in claim 1 wherein said catalyst is a salt of anacid selected from the group consisting of methane sulphonic acid,toluene-p-sulphonic acid, p-xylene sulphonic acid,naphthalene-Z-sulphonic acid and pyridyl sulphonic acid.

3. A process as defined in claim 1 wherein said 5 catalyst is a salt oforthophosphoric acid.

4. A process as defined in claim 1 wherein said catalyst is a salt of anacid selected from the group consisting of a lower alkyl phosphonic acidan a chloro-, bromoor iodosubstituted lower alkyl phosphonic acid.

5. A process as defined inclaim 1 wherein said catalyst is a salt of anacid selected from the group consisting of methane phosphonic acid,ethane phosphonic acid, trichloromethane phosphonic acid, iodomethanephosphonic acid and dichloromethane phosphonic acid.

6. A process as defined in claim 1 wherein said catalyst is a salt of anacid selected from the group consistjn of benzene phosphonic acid, achloro-, bromoor 10 o-benzene phosphonic acid and a mitro-benzenephosphonic acid.

7. A process as defined in claim 1 wherein said catalyst is a salt of anunsaturated heterocyclic tertiary base selected from the groupconsisting of pyridine, quinoline, isoquinoline, benzimidazole andpyridine, quinoline, isoquinoline or benzimidazole substituted by alower alkyl group.

8. A process as defined in claim 1 wherein said catalyst is a salt of amember selected from the group consisting of aniline, a chloroaniline, alower alkyl aniline, a hydroxy aniline, a lower aikoxy aniline, anitroaniline, a carboxyaniline and a N-lower alkyl aniline.

9. A process as defined in claim 1 wherein said salt is obtained by thereaction of substantially molar equivalents of an acid selected from thegroup consisting of a phosphorus acid, methane sulphonic acid, toluenep-sulphonic acid, p-xylene sulphonic acid and pyridine sulphonic acidwith said amine.

10. A process as defined in claim 1 wherein said salt is formed from anamine selected from the group consisting of pyridine; 2-methyl-,3-methyland 4-methylpyridines; quinoline and isoquinoline and an acidselected from the group consisting of orthophosphoric, methanephosphonic, ethane phosphonic, iodomethane phosphonic, dichloromethanephosphonic, trichloromethane phosphonic, bromobenzene phosphonic andnitrobenzene phosphonic acids.

11. A process as defined in claim 1 wherein said salt is obtained insitu by the reaction of substantially molar equivalents of pyridine andorthophosphoric acid.

12. A process as defined in claim 1 wherein said salt is obtained by thereaction of substantially molar equivalents of pyridine anddichloromethane phosphonic acid.

13. A process as defined in claim 1 wherein said salt is obtained by thereaction of about two molar equivalents of pyridine and one molarequivalent of dichloromethane phosphonic acid.

14. A process as defined in claim 1 in which a proportion of said saltnot exceeding 1.0 mole per mole of penicillin oxide is used.

15. A process as defined in claim 14 wherein the proportion of said saltis from 0.01 to 0.2 mole per mole of penicillin oxide.

16. A process as defined in claim 1 wherein the organic solvent isdioxan.

17. A process as defined in claim 1 wherein said solvent selected fromthe group consisting of ethyl methyl ketone, iso-butyl methyl ketone,methyl n-propyl ketone, n-propyl acetate, n-butyl acetate, iso-butylacetate, sec-butyl acetate, diethyl carbonate and diethylene glycoldimethyl ether.

18. A process as defined in claim 1 in which the reaction is effected atthe boiling point of the solvent and wherein a desiccating agent, whichis inert under the reaction conditions, is inserted in a reflux returnline to remove water formed during the reaction.

2. A process as defined in claim 1 wherein said catalyst is a salt of anacid selected from the group consisting of methane sulphonic acid,toluene-p-sulphonic acid, p-xylene sulphonic acid,naphthalene-2-sulphonic acid and pyridyl sulphonic acid.
 3. A process asdefined in claim 1 wherein said catalyst is a salt of orthophosphoricacid.
 4. A process as defined in claim 1 wherein said catalyst is a saltof an acid selected from the group consisting of a lower alkylphosphonic acid an a chloro-, bromo- or iodo- substituted lower alkylphosphonic acid.
 5. A process as defined in claim 1 wherein saidcatalyst is a salt of an acid selected from the group consisting ofmethane phosphonic acid, ethane phosphonic acid, trichloromethanephosphonic acid, iodomethane phosphonic acid and dichloromethanephosphonic acid.
 6. A process as defined in claim 1 wherein saidcatalyst is a salt of an acid selected from the group consisting ofbenzene phosphonic acid, a chloro-, bromo- or iodo-benzene phosphonicacid and a mitro-benzene phosphonic acid.
 7. A process as defined inclaim 1 wherein said catalyst is a salt of an unsaturated heterocyclictertiary base selected from the group consisting of pyridine, quinoline,isoquinoline, benzimidazole and pyridine, quinoline, isoquinoline orbenzimidazole substituted by a lower alkyl group.
 8. A process asdefined in claim 1 wherein said catalyst is a salt of a member selectedfrom the group consisting of aniline, a chloroaniline, a lower alkylaniline, a hydroxy aniline, a lower alkoxy aniline, a nitroaniline, acarboxyaniline and a N-lower alkyl aniline.
 9. A process as defined inclaim 1 wherein said salt is obtained by the reaction of substantiallymolar equivalents of an acid selected from the group consisting of aphosphorus acid, methane sulphonic acid, toluene p-sulphonic acid,p-xylene sulphonic acid and pyridine sulphonic acid with said amine. 10.A process as defined in claim 1 wherein said salt is formed from anamine selected from the group consisting of pyridine; 2-methyl-,3-methyl- and 4-methyl-pyridines; quinoline and isoquinoline and an acidselected from the group consisting of orthophosphoric, methanephosphonic, ethane phosphonic, iodomethane phosphonic, dichloromethanephosphonic, trichloromethane phosphonic, bromobenzene phosphonic andnitrobenzene phosphonic acids.
 11. A process as defined in claim 1wherein said salt is obtained in situ by the reaction of substantiallymolar equivalents of pyridine and orthophosphoric acid.
 12. A process asdefined in claim 1 wherein said salt is obtained by the reaction ofsubstantially molar equivalents of pyridine and dichloromethanephosphonic acid.
 13. A process as defined in claim 1 wherein said saltis obtained by the reaction of about two molar equivalents of pyridineand one molar equivalent of dichloromethane phosphonic acid.
 14. Aprocess as defined in claim 1 in which a proportion of said salt notexceeding 1.0 mole per mole of penicillin oxide is used.
 15. A processas defined in claim 14 wherein the proportion of said salt is from 0.01to 0.2 mole per mole of penicillin oxide.
 16. A process as defined inclaim 1 wherein the organic solvent is dioxan.
 17. A process as definedin claim 1 wherein said solvent selected from the group consisting ofethyl methyl ketone, iso-butyl methyl ketone, methyl n-propyl ketone,n-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate,diethyl carbonate and diethylene glycol dimethyl ether.
 18. A process asdefined in claim 1 in which the reaction is effected at the boilingpoint of the solvent and wherein a desiccating agent, which is inertunder the reaction conditions, is inserted in a reflux return line toremove water formed during the reaction.